JP3127933B2 - Positive photoresist developer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive photoresist developing solution, and more particularly to a developing solution comprising a quaternary ammonium hydroxide aqueous solution and a saccharide or a sugar alcohol. It is a positive photoresist developer that can form a fine pattern, has less variation in pattern dimensions, and can provide an excellent pattern profile, and is useful for the manufacture of ultrafine processed semiconductor integrated circuits.

[0002]

2. Description of the Related Art In recent years, the development of the electronics industry has been remarkable, and recent semiconductor integrated circuits have become highly integrated as typified by VLSI, and accordingly the minimum line width for drawing circuits has been gradually reduced, and resist patterns have been increasingly developed. It is strongly demanded to form a high precision. Positive resists can meet such demands, and have higher resolution than conventionally used negative resists. A typical positive resist contains both an alkali-soluble novolak resin as a base and a naphthoquinonediazide compound as a photolytic agent. An alkali aqueous solution is generally used as a developer for the naphthoquinone azide-based positive resist. However, when a semiconductor integrated circuit device is manufactured, it is preferable to use an alkali aqueous solution containing no metal ions in the developer. Needless to say. Therefore, an organic alkali developer containing no metal ion, for example, an aqueous solution of tetramethylammonium hydroxide, choline, or the like is known. (IBM
"Technical Disclosure Bulettin" Volume 13, Issue 7,
(Page 2009, 1970, U.S. Patent No. 4,239,661)

However, when a pattern with a fine line width is drawn using an aqueous solution of tetramethylammonium hydroxide or choline, the resist profile and the dimensional control accuracy are extremely reduced. For this reason, in order to increase the resist sensitivity, the alkali concentration of the developer is increased or the development time is lengthened, but a sufficient effect on the so-called throughput cannot be improved. In addition to this, various additives are added to the quaternary ammonium hydroxide aqueous solution as an improvement for improving resolution, for example, a surfactant,
The addition of an organic compound has been proposed. Examples of those containing a surfactant include, for example, JP-A-58-914.
No. 3, JP-A-61-70551, JP-A-61-167
No. 48, JP-A-61-151537, JP-A-61-2
No. 32453, JP-A-61-232454, JP-A-61-234454
JP-A-2-32452, JP-A-62-32454, JP-A-62-47125, etc. Examples of a surfactant obtained by further adding another organic compound such as an alcohol or a hydrocarbon to a surfactant are disclosed in For example, JP-A-62-232453, JP-A-58-57128 and the like. However, even in these cases, there are advantages and disadvantages, and it is hard to say that resolution, dimensional accuracy, and the like are necessarily satisfactory in lithography with a fine line width.

[0004] The present inventors have previously proposed a positive photoresist developer in which hydrazine or hydrazine and a surfactant are combined with a quaternary ammonium hydroxide aqueous solution. This is an excellent developer with a finer line width pattern profile and less scum than conventional alkaline developers.However, in the case of obtaining a more advanced ultra-fine line width lithography, resolution and dimensional accuracy Is now one step insufficient in stability and not satisfactory.

On the other hand, the present inventors have formulated saccharides or sugar alcohols in a quaternary ammonium hydroxide aqueous solution as a surface treatment solution for preventing aluminum corrosion caused by halogen in an aluminum wiring substrate by dry etching. An aqueous solution was previously proposed (Japanese Patent Application No. 14554/1990).

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention provides a positive resist capable of obtaining an excellent resist pattern profile with high resolution and capable of forming an ultra-fine pattern with small variations in pattern dimensions. To provide a mold photoresist developer.

[0007]

Means for Solving the Problems The present inventors have conducted various studies on an organic alkali-based positive resist developing solution, and added xylitol to an aqueous quaternary ammonium hydroxide solution.
It has been found that an aqueous solution to which sorbitol or sorbitol is added and blended enables stable and highly precise ultrafine processing and gives an excellent pattern profile. That is, the present invention relates to a compound represented by the general formula: [(R ¹ ) ₃ NR] ⁺
· OH - ^(wherein R is an alkyl group having 1 to 3 carbon atoms or hydroxy-substituted alkyl group having 1 to 3 carbon atoms,, R ¹ represents an alkyl group having 1 to 3 carbon atoms) a is represented by 1 to 10% by weight of quaternary ammonium hydroxide aqueous solution and xylitol
Or a positive type photoresist developer containing 0.5 to 3% by weight of sorbitol .

In the present invention, the quaternary ammonium hydroxide represented by the above general formula is a tetraalkylammonium hydroxide having an alkyl group having 1 to 3 carbon atoms or a trialkylammonium hydroxide having R as a hydroxy-substituted alkyl group. Alkyl (hydroxyalkyl) ammonium hydroxide,
Specifically, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, trimethylethylammonium hydroxide, trimethyl (2-hydroxyethyl) ammonium hydroxide, triethyl (2- (Hydroxyethyl) ammonium hydroxide, tripropyl (2-hydroxyethyl) ammonium hydroxide, trimethyl (1-hydroxypropyl) ammonium hydroxide and the like.
Of these, particularly preferred are tetramethylammonium hydroxide (hereinafter sometimes referred to as "TMAH") and trimethyl (2-hydroxyethyl) ammonium hydroxide (hereinafter sometimes referred to as "choline"). .

The above quaternary ammonium hydroxide is generally selected in a concentration range of 1 to 10% by weight in the whole solution, and in actual use, an appropriate concentration is selected depending on the kind of the compound to be used. . For example, in the case of choline or tetraethylammonium hydroxide, the concentration needs to be at least 5% by weight. When the concentration is lower than 5% by weight, development cannot be performed sufficiently, and sometimes development cannot be performed. This is inconvenient because it is not formed and scum is generated so that a good pattern cannot be formed. TMAH
In the case of (3), a concentration in the range of 3% by weight to 4% by weight is selected. At a high concentration of 5% by weight such as choline, the rate of decreasing the thickness of the unexposed portion becomes too fast, and the resist dissolves to form a fine pattern. Can not. In order to stably obtain a good pattern profile as described above, it is necessary to appropriately select the use concentration depending on the compound used.

Next, the sugar alcohols used together with the quaternary ammonium hydroxide in the present invention include xylitol and sorbitol. These sugar alcohols are generally used in a concentration range of 0.1 to 3% by weight, preferably 0.5 to 3% by weight in the total solution. When the concentration is lower than the above range, it is difficult to form an ultrafine pattern with high accuracy. On the other hand, when the concentration is higher than 3% by weight, the film loss rate of the exposed portion of the resist is reduced and a good pattern is not formed. Function cannot be exhibited.

The developer in the present invention can be applied to any method such as an immersion method, a spray method, and a paddle method. The temperature and time for development are appropriately selected according to the type of the resist. When a resist composed of an alkali-soluble novolak resin containing a naphthoquinone azide compound is used and developed by an immersion method, a pattern formation which can be sufficiently satisfied with the temperature (room temperature) and the development time generally used so far is generally used. Is possible.

Hereinafter, the present invention will be described in more detail with reference to examples.

【Example】

Example 1 [Preparation of resist pattern for test] OFPR-80 containing an alkali-soluble novolak resin and a naphthoquinonediazide compound as constituents on a 3-inch silicon wafer
0 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) using a spinner to obtain a film thickness of 1.2 μm.
m in a clean oven.
After pre-baking at 30 ° C. for 30 minutes, exposure processing was performed through a test chart reticle using a contact exposure apparatus.
Since the dissolution rate of the resist varies depending on the amount of sorbitol added, the optimal exposure was measured in advance for the optimal exposure. [Preparation of Developing Solution] Sorbitol was added to a 2.38% by weight aqueous solution of tetramethylammonium hydroxide (TMAH) in the amount shown in Table 1 to prepare a developing solution, which was subjected to a test. For comparison, those without sorbitol added,
Further, polyethylene glycol added instead of sorbitol was prepared and used for the test. [Development test] After developing using the respective developing solutions shown in Table 1 under a developing condition of 23 ° C and 60 seconds by an immersion method, a rinsing treatment was performed with ultrapure water, and the solution was heated at 120 ° C in a clean oven. Post bake was performed for 30 minutes. Thereafter, the film thickness reduction rate of the unexposed portion and the taper angle of the cross-sectional shape of the developed resist pattern were measured or observed. The taper angle of the cross-sectional shape was 0.75 on the developed resist film.
The cross-sectional shape of the μm line pattern was observed and measured with a scanning electron microscope. As is evident from Table 1, the developing solution of the present invention sufficiently suppresses the reduction rate of the film thickness in the unexposed portion, and obtains a sharp pattern line having a high taper angle.

[0014]

[Table 1]

Example 2 Xylitol was used as a sugar or a sugar alcohol,
A resist pattern similar to that in Example 1 was used under the same developing conditions except that a developer prepared at a concentration of 3% by weight was used. Table 2 shows the results.

[0016]

[Table 2]

Reference Example A saccharose was used as a sugar or a sugar alcohol, and a developer prepared at a concentration of 3% by weight was used.
The same resist pattern as in Example 1 was performed under the same developing conditions. Table 3 shows the results.

[0018]

[Table 3]

Example 4 Sorbitol was added to a 5% by weight aqueous solution of choline in the amount shown in Table 4 to prepare a developer, which was subjected to a test. The resist pattern used for the test was the same as that used in Example 1, and the results obtained under the same development conditions as in Example 1 are shown in Table-4.

[0020]

[Table 4]

Example 5 Sorbitol was added to a 6% by weight aqueous solution of tetraethylammonium hydroxide in an amount shown in Table 5 to prepare a developer, which was subjected to a test. The same resist pattern as that used in Example 1 was used for the test, and the results obtained by performing the development under the same developing conditions as in Example 1 are shown in Table-5.

[0022]

[Table 5]

[0023]

The developing solution of the present invention sufficiently suppresses the rate of film thickness reduction in the unexposed area, enables formation of an ultra-fine pattern with high resolution, and has a very small variation in pattern dimensions, and is stable. And has an excellent effect such as being able to give a good pattern profile, and is extremely useful industrially.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-87838 (JP, A) JP-A-64-19344 (JP, A) JP-A-63-259560 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) G03F 7/32 H01L 21/027

Claims (2)

(57) [Claims] 1. A compound represented by the general formula: [(R ¹ ) ₃ N—R] ⁺ .OH
^- (wherein R is an alkyl group having 1 to 3 carbon atoms or hydroxy-substituted alkyl group having 1 to 3 carbon atoms,, R ¹ represents an alkyl group having 1 to 3 carbon atoms) quaternary represented by 1 to 10% by weight of aqueous ammonium hydroxide solution and xylitol
Or a positive type photoresist developer containing 0.5 to 3% by weight of sorbitol . 2. The quaternary ammonium hydroxide represented by the general formula is a tetramethylammonium hydroxide, a tetraethylammonium hydroxide, or a trimethyl (2-hydroxyethyl) ammonium hydroxide. The developer according to claim 1.